This invention relates to an induction system for internal combustion engines and more particularly to an improved, compact, high-efficiency induction system for a V-type engine.
As is well known, the induction system for an internal combustion engine is very instrumental in determining the performance of the engine. Generally, the induction system is designed so as to provide an intake manifold which delivers air from an atmospheric source to the intake passages of the cylinder heads. As is well known, the length of the intake passages that serve the individual cylinders is very instrumental in determining the performance of the engine. It has also been, the practice to provide compound induction systems wherein runners of different effective lengths can serve each combustion chamber.
It has also been found desirable to provide a plenum device for the induction system into which the individual manifold runners open. Air is introduced from the atmosphere into this plenum device and then from the plenum device to the individual runners for serving the cylinders. The use of the plenum device permits a common inlet to serve several cylinders without the pulsations from one cylinder from adversely effecting other cylinders.
It should be readily apparent from the foregoing description that the induction system can occupy a fairly substantial area. This is a particular problem with automotive engines and engines in various other applications where space constraints and engine height are particularly important factors.
It is, therefore, a principal object of this invention to provide an improved and compact induction system for an internal combustion engine.
The problems aforenoted are particularly acute in conjunction with V-type engines. V-type engines are preferred in many applications because the orientation of the cylinders permits a more compact engine. Also, by inclining the cylinder banks at an angle to each other, the overall height of the engine can be reduced, although the width is increased.
For a variety of reasons, it has been the practice with V-type engines to position the induction system in the area or valley formed between the cylinder banks. By using this otherwise void area, the construction can be made more compact.
One way in which the system can be made compact is by positioning the plenum chamber at the lower portion of the valley. The manifold runners then can extend upwardly from the plenum chamber and across the upper portion of the valley to the cylinder head intake passages. This provides a relatively compact assembly.
With type of arrangement, however, it has been the practice to provide the atmospheric air inlet to the plenum chamber at one end of the plenum chamber. Frequently, the throttle valve for the engine or throttles valves are positioned at or in this atmospheric air inlet.
It has been found, however, that this type of arrangement has some disadvantages. First, because the atmospheric air is delivered to the plenum chamber at one of its ends, there may be an uneven distribution of air to the individual cylinders of the engine. This, obviously, adversely affects engine performance. Another problem which has been found to be attendant with this type of induction system is that the induction system generates what may be characterized as a rumbling noise.
It is, therefore, a further object of this invention to provide an induction system of this type wherein the induction system can be compact and also wherein equal air distribution to the cylinders is provided and the rumbling noise substantially eliminated.